Btrfs: qgroup: Introduce a may_use to account space_info->bytes_may_use.

Currently, for pre_alloc or delay_alloc, the bytes will be accounted
in space_info by the three guys.
space_info->bytes_may_use --- space_info->reserved --- space_info->used.
But on the other hand, in qgroup, there are only two counters to account the
bytes, qgroup->reserved and qgroup->excl. And qg->reserved accounts
bytes in space_info->bytes_may_use and qg->excl accounts bytes in
space_info->used. So the bytes in space_info->reserved is not accounted
in qgroup. If so, there is a window we can exceed the quota limit when
bytes is in space_info->reserved.

Example:
	# btrfs quota enable /mnt
	# btrfs qgroup limit -e 10M /mnt
	# for((i=0;i<20;i++));do fallocate -l 1M /mnt/data$i; done
	# sync
	# btrfs qgroup show -pcre /mnt
qgroupid rfer     excl     max_rfer max_excl parent  child
-------- ----     ----     -------- -------- ------  -----
0/5      20987904 20987904 0        10485760 ---     ---

qg->excl is 20987904 larger than max_excl 10485760.

This patch introduce a new counter named may_use to qgroup, then
there are three counters in qgroup to account bytes in space_info
as below.
space_info->bytes_may_use --- space_info->reserved --- space_info->used.
qgroup->may_use           --- qgroup->reserved     --- qgroup->excl

With this patch applied:
	# btrfs quota enable /mnt
	# btrfs qgroup limit -e 10M /mnt
	# for((i=0;i<20;i++));do fallocate -l 1M /mnt/data$i; done
fallocate: /mnt/data9: fallocate failed: Disk quota exceeded
fallocate: /mnt/data10: fallocate failed: Disk quota exceeded
fallocate: /mnt/data11: fallocate failed: Disk quota exceeded
fallocate: /mnt/data12: fallocate failed: Disk quota exceeded
fallocate: /mnt/data13: fallocate failed: Disk quota exceeded
fallocate: /mnt/data14: fallocate failed: Disk quota exceeded
fallocate: /mnt/data15: fallocate failed: Disk quota exceeded
fallocate: /mnt/data16: fallocate failed: Disk quota exceeded
fallocate: /mnt/data17: fallocate failed: Disk quota exceeded
fallocate: /mnt/data18: fallocate failed: Disk quota exceeded
fallocate: /mnt/data19: fallocate failed: Disk quota exceeded
	# sync
	# btrfs qgroup show -pcre /mnt
qgroupid rfer    excl    max_rfer max_excl parent  child
-------- ----    ----    -------- -------- ------  -----
0/5      9453568 9453568 0        10485760 ---     ---

Reported-by: Cyril SCETBON <cyril.scetbon@free.fr>
Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 695d5110e02057abf9f8b3f4a0f1cbf878a6441d..3113e0b79b9981333463e7ede67aa6334b34cf9c 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -5725,8 +5725,12 @@ static int pin_down_extent(struct btrfs_root *root,
 
        set_extent_dirty(root->fs_info->pinned_extents, bytenr,
                         bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
-       if (reserved)
+       if (reserved) {
+               btrfs_qgroup_update_reserved_bytes(root->fs_info,
+                                                  root->root_key.objectid,
+                                                  num_bytes, -1);
                trace_btrfs_reserved_extent_free(root, bytenr, num_bytes);
+       }
        return 0;
 }
 
@@ -6464,6 +6468,9 @@ void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
                btrfs_put_block_group(cache);
                trace_btrfs_reserved_extent_free(root, buf->start, buf->len);
                pin = 0;
+               btrfs_qgroup_update_reserved_bytes(root->fs_info,
+                                                  root->root_key.objectid,
+                                                  buf->len, -1);
        }
 out:
        if (pin)
@@ -7196,7 +7203,11 @@ static int __btrfs_free_reserved_extent(struct btrfs_root *root,
                        ret = btrfs_discard_extent(root, start, len, NULL);
                btrfs_add_free_space(cache, start, len);
                btrfs_update_reserved_bytes(cache, len, RESERVE_FREE, delalloc);
+               btrfs_qgroup_update_reserved_bytes(root->fs_info,
+                                                  root->root_key.objectid,
+                                                  len, -1);
        }
+
        btrfs_put_block_group(cache);
 
        trace_btrfs_reserved_extent_free(root, start, len);
@@ -7433,6 +7444,9 @@ int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
        BUG_ON(ret); /* logic error */
        ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
                                         0, owner, offset, ins, 1);
+       btrfs_qgroup_update_reserved_bytes(root->fs_info,
+                                          root->root_key.objectid,
+                                          ins->offset, 1);
        btrfs_put_block_group(block_group);
        return ret;
 }
@@ -7579,6 +7593,10 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
                return ERR_PTR(ret);
        }
 
+       btrfs_qgroup_update_reserved_bytes(root->fs_info,
+                                          root_objectid,
+                                          ins.offset, 1);
+
        buf = btrfs_init_new_buffer(trans, root, ins.objectid, level);
        BUG_ON(IS_ERR(buf)); /* -ENOMEM */
 

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 6ef97c184c7b3742ae5e35cd57ae0849c6930830..a9f69a0d4b08ba88f11736d1f8052a5aed2a555b 100644 (file)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -60,6 +60,7 @@
 #include "backref.h"
 #include "hash.h"
 #include "props.h"
+#include "qgroup.h"
 
 struct btrfs_iget_args {
        struct btrfs_key *location;
@@ -753,7 +754,9 @@ retry:
                        }
                        goto out_free;
                }
-
+               btrfs_qgroup_update_reserved_bytes(root->fs_info,
+                                                  root->root_key.objectid,
+                                                  ins.offset, 1);
                /*
                 * here we're doing allocation and writeback of the
                 * compressed pages
@@ -978,6 +981,10 @@ static noinline int cow_file_range(struct inode *inode,
                if (ret < 0)
                        goto out_unlock;
 
+               btrfs_qgroup_update_reserved_bytes(root->fs_info,
+                                                  root->root_key.objectid,
+                                                  ins.offset, 1);
+
                em = alloc_extent_map();
                if (!em) {
                        ret = -ENOMEM;
@@ -7030,6 +7037,10 @@ static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
                return ERR_PTR(ret);
        }
 
+       btrfs_qgroup_update_reserved_bytes(root->fs_info,
+                                          root->root_key.objectid,
+                                          ins.offset, 1);
+
        return em;
 }
 
@@ -9583,6 +9594,11 @@ static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
                                btrfs_end_transaction(trans, root);
                        break;
                }
+
+               btrfs_qgroup_update_reserved_bytes(root->fs_info,
+                                                  root->root_key.objectid,
+                                                  ins.offset, 1);
+
                btrfs_drop_extent_cache(inode, cur_offset,
                                        cur_offset + ins.offset -1, 0);
 

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index de321c90130c05f498489d171ed958bdae4063c9..cd291733dc3e537bcfbd0f710c78c71cdeb61394 100644 (file)
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -72,6 +72,7 @@ struct btrfs_qgroup {
        /*
         * reservation tracking
         */
+       u64 may_use;
        u64 reserved;
 
        /*
@@ -1417,6 +1418,8 @@ static int qgroup_excl_accounting(struct btrfs_fs_info *fs_info,
        WARN_ON(sign < 0 && qgroup->excl < oper->num_bytes);
        qgroup->excl += sign * oper->num_bytes;
        qgroup->excl_cmpr += sign * oper->num_bytes;
+       if (sign > 0)
+               qgroup->reserved -= oper->num_bytes;
 
        qgroup_dirty(fs_info, qgroup);
 
@@ -1436,6 +1439,8 @@ static int qgroup_excl_accounting(struct btrfs_fs_info *fs_info,
                qgroup->rfer_cmpr += sign * oper->num_bytes;
                WARN_ON(sign < 0 && qgroup->excl < oper->num_bytes);
                qgroup->excl += sign * oper->num_bytes;
+               if (sign > 0)
+                       qgroup->reserved -= oper->num_bytes;
                qgroup->excl_cmpr += sign * oper->num_bytes;
                qgroup_dirty(fs_info, qgroup);
 
@@ -2378,6 +2383,61 @@ out:
        return ret;
 }
 
+int btrfs_qgroup_update_reserved_bytes(struct btrfs_fs_info *fs_info,
+                                           u64 ref_root,
+                                           u64 num_bytes,
+                                           int sign)
+{
+       struct btrfs_root *quota_root;
+       struct btrfs_qgroup *qgroup;
+       int ret = 0;
+       struct ulist_node *unode;
+       struct ulist_iterator uiter;
+
+       if (!is_fstree(ref_root) || !fs_info->quota_enabled)
+               return 0;
+
+       if (num_bytes == 0)
+               return 0;
+
+       spin_lock(&fs_info->qgroup_lock);
+       quota_root = fs_info->quota_root;
+       if (!quota_root)
+               goto out;
+
+       qgroup = find_qgroup_rb(fs_info, ref_root);
+       if (!qgroup)
+               goto out;
+
+       ulist_reinit(fs_info->qgroup_ulist);
+       ret = ulist_add(fs_info->qgroup_ulist, qgroup->qgroupid,
+                       (uintptr_t)qgroup, GFP_ATOMIC);
+       if (ret < 0)
+               goto out;
+
+       ULIST_ITER_INIT(&uiter);
+       while ((unode = ulist_next(fs_info->qgroup_ulist, &uiter))) {
+               struct btrfs_qgroup *qg;
+               struct btrfs_qgroup_list *glist;
+
+               qg = u64_to_ptr(unode->aux);
+
+               qg->reserved += sign * num_bytes;
+
+               list_for_each_entry(glist, &qg->groups, next_group) {
+                       ret = ulist_add(fs_info->qgroup_ulist,
+                                       glist->group->qgroupid,
+                                       (uintptr_t)glist->group, GFP_ATOMIC);
+                       if (ret < 0)
+                               goto out;
+               }
+       }
+
+out:
+       spin_unlock(&fs_info->qgroup_lock);
+       return ret;
+}
+
 /*
  * reserve some space for a qgroup and all its parents. The reservation takes
  * place with start_transaction or dealloc_reserve, similar to ENOSPC
@@ -2426,14 +2486,14 @@ int btrfs_qgroup_reserve(struct btrfs_root *root, u64 num_bytes)
                qg = u64_to_ptr(unode->aux);
 
                if ((qg->lim_flags & BTRFS_QGROUP_LIMIT_MAX_RFER) &&
-                   qg->reserved + (s64)qg->rfer + num_bytes >
+                   qg->reserved + qg->may_use + (s64)qg->rfer + num_bytes >
                    qg->max_rfer) {
                        ret = -EDQUOT;
                        goto out;
                }
 
                if ((qg->lim_flags & BTRFS_QGROUP_LIMIT_MAX_EXCL) &&
-                   qg->reserved + (s64)qg->excl + num_bytes >
+                   qg->reserved + qg->may_use + (s64)qg->excl + num_bytes >
                    qg->max_excl) {
                        ret = -EDQUOT;
                        goto out;
@@ -2457,7 +2517,7 @@ int btrfs_qgroup_reserve(struct btrfs_root *root, u64 num_bytes)
 
                qg = u64_to_ptr(unode->aux);
 
-               qg->reserved += num_bytes;
+               qg->may_use += num_bytes;
        }
 
 out:
@@ -2503,7 +2563,7 @@ void btrfs_qgroup_free(struct btrfs_root *root, u64 num_bytes)
 
                qg = u64_to_ptr(unode->aux);
 
-               qg->reserved -= num_bytes;
+               qg->may_use -= num_bytes;
 
                list_for_each_entry(glist, &qg->groups, next_group) {
                        ret = ulist_add(fs_info->qgroup_ulist,

diff --git a/fs/btrfs/qgroup.h b/fs/btrfs/qgroup.h
index c5242aa9a4b2a1cc7237bd42487c063a0790d87f..64d49b8482b302058fc50d4162a36a67f4a8cb78 100644 (file)
--- a/fs/btrfs/qgroup.h
+++ b/fs/btrfs/qgroup.h
@@ -94,6 +94,10 @@ int btrfs_run_qgroups(struct btrfs_trans_handle *trans,
 int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans,
                         struct btrfs_fs_info *fs_info, u64 srcid, u64 objectid,
                         struct btrfs_qgroup_inherit *inherit);
+int btrfs_qgroup_update_reserved_bytes(struct btrfs_fs_info *fs_info,
+                                      u64 ref_root,
+                                      u64 num_bytes,
+                                      int sign);
 int btrfs_qgroup_reserve(struct btrfs_root *root, u64 num_bytes);
 void btrfs_qgroup_free(struct btrfs_root *root, u64 num_bytes);